Unlocking the Codex harness: how we built the App Server

Practical AI: Tools, Models & Frameworksapi

What changed

Learn how to embed the Codex agent using the Codex App Server, a bidirectional JSON-RPC API powering streaming progress, tool use, approvals, and diffs.

Why it matters

A concrete addition to Practical AI: Tools, Models & Frameworks: it changes what's available to builders today rather than being general commentary.

How it compares

Related prior coverage to compare against:

  • Introducing Codex
  • Introducing the Codex app
  • Powering next generation applications with OpenAI Codex

Sources